This invention is directed to a novel safety razor construction and more particularly directed to a flexible razor blade assembly.
Since the introduction of the safety razor, the blade assembly has consisted principally of three members, namely, a handle, a guard bar and seat combination, and a cap. The function of the guard bar/seat and cap is to properly locate and hold the blade in the proper location for cutting hair in controlled contact with the skin. Generally these elements have been manufactured as separate components which, when removably attached or fixedly attached to the handle, combine to maintain desired geometry in relationship of these elements during the act of shaving.
Of more recent development is the bonded cartridge or razor blade assembly in which the seat, cap and blade are permanently and rigidly bonded together to achieve and maintain a desired shaving geometry and fixed relationship of the parts. In this arrangement, the cartridge is adapted to be coupled as a complete and unitary assembly to the handle. This type of configuration is exemplified and disclosed in U.S. Pat. No. 3,783,510, which employs a tandem or twin blade assembly with a spacer therebetween permanently and rigidly bonded to a cap and platform member, the platform member or seat having an integral guard bar and coupling members for attachment to the handle.
The advantage of the bonded cartridge is mainly one of convenience. It achieves no more than prior art shaving systems previously described, i.e., discrete components assembled to the razor handle, but it does provide some ease of handling with a concomitant increase in price.
There have been attempts to alter the operation and geometrical relationships of the blade assembly to achieve increased shaving comfort and efficiency. U.S. Pat. No. 1,383,783 describes a shaving system having a number of parallel arrayed blades fixed to a flexible support or platform, the purpose of the flexible support being to provide or enable the razor to adapt itself to contours of the face while being moved thereover. The platform of this prior art device is flexible about an axis parallel to the plane of the blades and to the edges thereof; hence such structure fails to permit the blade itself to conform to facial or body contours.
Another attempt to fashion a blade assembly adaptable to user requirements is described in U.S. Pat. No. 3,500,539. The device described therein utilizes a tranvsersely arrayed guard bar connected to the blade platform by a yieldable web structure. Dependent upon the applied shaving force, the orientation of the guard with respect to the blade edge is altered resulting in changing blade exposure, blade tangent angle, and shaving angle. These terms are defined as follows: The blade exposure is the normal distance the blade edge extends above or below a plane tangent to the cap and guard bar; the blade tangent angle is the angle formed between a plane tangent to the blade edge and the guard bar and a second plane bisecting the blade edge; the shaving angle is the angle formed between the plane bisecting the blade edge and the plane tangent to the cap and guard bar. Theoretically, this type of arrangement might permit a shaver to select desired geometry by the application of a controlled force. However, in practical application, the achieving of the desired geometry in this fashion has proven difficult. It is further pointed out that the structure of this patent fails to provide for adaptability to the contours of the shaver's face or body.
Applicants have realized the desirability of a shaving system which would maintain uniform, consistent geometry when in use but which would also allow the blade to substantially conform to the contours of the skin surface in order to achieve greater comfort, safety and efficiency. Such a system would allow selection of optimum shaving geometry and, if given sufficient flexibility, would permit the maintenance of optimum geometry while the system was conforming to varying contours. Flexing of the assembly may be derived through mechanical or structural changes of the blade assembly or through the utilization of materials which allow the cap and seat to yieldingly follow changing contours. In using a device of this nature, the cutting edge is allowed to stay in contact with a maximum amount of skin surface despite undulations therein, which a non-flexible system might only achieve when shaving a surface parallel to the blade edge. Obviously, the latter surface is unavailable on the human body.
As used herein, the term "flexible" is intended to include a bending capability sufficient to conform to many shaved non-planar surfaces in response to normal human shaving forces, and to exclude the relatively rigid prior art shaving assemblies which yield or bend no more than an insignificant amount insofar as contour-following characteristics are concerned.
As used herein, the phrase "yieldingly bonded" refers to arrangements including adhesives, relatively movable pinning, or the like for securing one part of a blade assembly to another part of that blade assembly such that some recoverable movement therebetween is allowed.
The intent of this invention is to define and provide a system which maintains uniform and consistent shaving geometry while substantially conforming to the contours of the skin surface. Another object of the invention is to provide a flexible razor blade assembly wherein the cutting edge is maintained in optimum contact with the skin surface. Yet another object of the invention is to provide a unitary bonded flexible shaving cartridge having at least one razor blade therein. Yet another object of the present invention is to provide a flexible cartridge in which the components thereof are yieldingly bonded together.